It is known to use artificial structures to assist muscular contraction. Such structures are adapted to assist atrial or ventricular contraction, or to assist or replace a natural sphincter. The use of such artificial sphincters has increased in recent years because faecal and urinary incontinences now affects more than 10% of people over 60 years of age and dramatically increases in patients over 80 years of age. Several pharmaceutical or surgical solutions have been developed for treating urinary and faecal incontinences. Generally, the outcome of surgery for treatment of urinary and faecal incontinence has to be regarded as low. The impacts on health care costs and overall quality of life of the patient are enormous.
The AMS800 artificial sphincter for urinary incontinence is commercialized by American Medical Systems and is composed of three components, a cuff, a pump, and a pressure-regulating balloon. The cuff is implanted at the bulbous urethra in males and is inflatable by means of a fluid. The pump is implanted in the scrotum and the pressure-regulating balloon is implanted in the abdomen. The major problems when using AMS800 is the tissue erosion around the urethra due to the constant pressure, the atrophy and irritation of tissues at the location of the inflatable cuff, and the emergency surgery for repair should the device remain in closed position in the event of mechanical failure. All other commercialized artificial sphincters whether for urinary or faecal incontinences bear similar drawbacks.
The ProAct™ device for urinary incontinence is commercialized by Uromedica and is composed of two small implantable balloons. During a short outpatient procedure, the balloons are surgically placed under the skin in the area where the prostate of the patient was surgically treated. The balloons help protect against accidental leaking of urine by increasing the amount of pressure required to urinate. When the patient needs to urinate, a normal amount of effort still should be required to push the urine out. However, the pressure from the balloons will help guard against unintentional urine loss, such as during a sneeze or cough. The major problems when using ProACT™ are identical to the problems using AMS800 artificial sphincter described above.
FlowSecure™, manufactured by Sterilin Ltd, another silicone hydraulic urinary sphincter similar to AMS800, has an extra pressure transmission balloon to transfer increased intra abdominal pressure directly to the cuff. Implantation of this device is technically feasible, but still difficult and is reported to be safe and effective in the short-term for the treatment of male urodynamic stress urinary incontinence, arising from a number of etiologies. However, the major problems when using FlowSecure™ are identical to the problems using AMS800 artificial sphincter described above.
Some publications describe the use of artificial sphincters comprising shape memory alloy elements suitable for opening and closing a part of an organ in a living body.
JP 07-051304 discloses a constrictor comprising two shape memory alloy elements with different shape memories, and covered by covering materials. The first covering material is formed in a shape to close the urethra in the daytime, and the second covering material is formed in a shape to half close the urethra in the night. This sphincter allows changing the pressure to the urethra, in order to prevent the incontinence in life action in the daytime, and to avoid necrosis of the tissue by loosing the pressure to the urethra in the night.
However, the drawbacks of such artificial sphincters are that there is a risk of tissue erosion and consequential necrosis, due to the high constant pressure to the urethra during the day and that there is a risk of incontinence during the night. If the shape memory alloy is no more efficient or is broken, the whole sphincter should be moved and replaced. Another risk is tissue erosion due to the high temperature of the shape memory alloy.
Moreover, JP 07-051304 discloses an artificial sphincter in which the shape memory alloy elements are disconnected from each other. This embodiment does not allow optimal pressure control.
Moreover, this kind of shape memory alloy elements uses a lot of power. That means that the battery needs to be changed very often or alternatively very large batteries have to be used.
EP 1 598 030 discloses an urine incontinence treatment apparatus, comprising a restriction device for engaging the urethra to form a restricted urine passageway in the urethra, the restriction device being operable to change the restriction of the urine passageway, a source of energy, and a control device operable from outside the patient's body for controlling the source of energy to release energy for use in connection with the operation of the restriction device, a motor or pump implantable in the patient, wherein the source of energy is adapted to power the motor or pump and the control device is adapted to control the motor or pump to operate the restriction device. The source of energy can be an internal battery with a lifetime of at least 10 years. However, as disclosed in EP 1 598 030, an internal battery is an advantageous solution for embodiments of the apparatus that have a relatively high consumption of energy, which cannot be satisfied by direct supply of wireless energy. Therefore, even if the lifetime of the internal battery is of 10 years, the operation time of said internal battery is shorter as the energy consumption is very high. Said internal battery should therefore be changed very often.
WO 2009/048399 discloses an apparatus for controlling a flow of sperms in an uterine tube, comprising an implantable flow influence device to be applied on at least one portion of the uterine tube. The energy source is an implantable primary battery or accumulator. Preferably the energy source is external and a control device controls the external energy source to transmit wireless energy from the outside of the patient's body to the inside. The energy will directly be used or the operation of the device e.g. to power the constriction/stimulation unit. The internal source may store energy. The constriction/stimulation device needs high energy to be activated but also to be maintained in an activated position. Therefore the preferable energy supply is the wireless transmission of energy. A drawback of wireless transmission is its efficiency. In case of using an accumulator for storing energy the accumulator has to be recharged frequently that reduces the lifetime of the accumulator.
WO 2009/004092 discloses an artificial structure comprising several contractile elements adapted to contract an organ by means of contractile fibers. Such fibers need high energy to be activated but also to be maintained in an activated position. As disclosed in WO 2009/004092 an implanted rechargeable battery needs to be recharged at least once a day using a battery volume in the range of this invention. Larger rechargeable batteries with more capacity exist but would not be possible to implant.
WO 2004/066879 discloses a male sexual impotence treatment apparatus, comprising a constriction member extending in a loop around the penile tissue. Wireless energy transfer is used to electrically power the constriction member during device operation that means external energy is wireless transmitted from the outside of the patient's body to the inside to recharge the implantable battery. The energy will directly be used or the operation of the device or to recharge the battery. The actuator is fixed on the constriction member in such a way that an electric wire linking the actuator to a source of energy goes through the body of the patient. A drawback of wireless transmission is its efficiency. Another drawback is the recharging of the battery. Small rechargeable batteries have to be replaced after about 1 year. Moreover, the electric wire should be designed to conduct a current in the order of milliamperes, which is needed for powering the operation device when operating the constriction device, so that the constriction device exerts a force strong enough to constrict the penile tissue or the prolongation thereof, so that the patient's penile exit blood flow is restricted. Thus the electric wire should have a low resistance.
No information is given, how much energy is needed to constrict the penile tissue and for how long. Based on the description and the drawings, continuous power is needed to hold the device in constrict position.
WO 2007/066344 discloses an implantable extra cardiac compression device for left ventricular assistance in severe heart failure. The device comprises metal flanges that are passively flexed at springed-hinges by a vertically moving metal cup. The flanges are connected to each other by a high-tensile, elastic polymer membrane. However, with such device, one flange, used alone, cannot contract the organ. Moreover, such device needs high energy to be activated but also to be maintained in an activated position. The external battery that may be recharged will be connected transcutaneously to the motor assembly placed inside the patient's abdomen. A transcutaneous connection always bears a risk of infection.
Moreover, when such implantable devices are placed in the body of a patient, they are on contact with body fluids. Moisture penetrates into the device and more specifically into the control unit and the actuator. Moisture condenses, and water propagates and reaches the control unit, in which corrosion starts. The drawback is that some parts are corroded, and more specifically, the electronic and mechanical parts of the control unit and the actuator.
U.S. Pat. No. 7,011,621 discloses a body fluid flow control device comprises a first engaging element and a second engaging element (called plunging member) forming an inner diameter when second member moves towards first member to encircle a body vessel. That means the plunging member moves and press one side of the organ. With other words motor drives the worm gear pulling the nut along with the casing and thus acts on the cable to push the plunging member to close the body fluid flow control or to pull on the plunging member using the cable to open the body fluid flow control. The described design has several disadvantages. First pushing the plunging member needs a quite stiff cable to apply the necessary pressure towards the vessel. Otherwise the cable would kink. Patient feels stiff sleeve including cable. The bending radius of a stiff cable is limited. This will limit the indications, e.g. the implantation of such a device close to the bladder neck is almost impossible. Second the inner diameter that is formed when the plunging member is moved towards the first engaging member is just in one limited case a circle, namely when the radius of the first engaging member and the plunging member are the same. Otherwise, and this will be the normal case using this design the enclosing form is like a lens or an oval leading to not evenly distributed pressure on the vessel. That means there are areas where the tissue will be compressed more than in other areas leading to tissue damage. Further the circumference of the vessel could be much bigger that the circumference built by the two members. That means that by moving the plunging member towards the first member vessel will be squeezed without being closed resulting in tissue damage. On the other hand the circumference of the vessel could be smaller than the circumference of the two members meaning that the vessel stays open, even the members are closed. Further, the vessel is pressed all the time except when e.g. the patient has to void. This leads to the same problem as for AMS 800 namely to tissue erosion around the vessel due to the constant pressure, the atrophy and irritation of tissues.
The disclosed concept is very energy consuming because energy is needed to maintain the closed position. There is no mechanism described that would keep the device in its closed position. Moreover in case of no power the closed position of the members cannot be hold because of vessel pressure and the motors turn back to a balanced position. But in this position the vessel is not closed anymore.
Moreover, U.S. Pat. No. 7,011,621 discloses the use of a magnetic coupling device placed between the casing and the cable. In this configuration, the magnetic field is not well shielded. That means that the magnetic field of the magnets will influence the reliability of the electromotor.
WO 99/48438 discloses an artificial sphincter system which comprises a first shell and a second shell for coupling with the second shell to form a cylindrical objective suitable for engaging and surrounding a selected canal with the host body. It also includes a plunger for constricting the fluid flow when activated. The host-user can activate the sphincter system with a remote control. The device also comprises a casing containing a piston-like mechanism for driving a plunger into the hollow portion of the device to restrict fluid flow through the canal enveloped by the device. The piston-like mechanism is preferably an electromechanical solenoid but any hydraulic, pneumatic, or equivalent piston-like mechanism can be used.
Piston-like or plunging member need power be stay in closed position. No information is provided about how much energy (current) is needed to open and close the piston-like or plunging member and keep closed position meaning continuous current would be needed to keep the sphincter closed.
US 2005/148814 discloses an electromechanical apparatus and method useful for augmenting muscle function. The method involves operating electrically operated actuators on an external surface of the muscle or organ. The carrier comprises electrically operated actuators arranged in a band, mesh, or other suitable arrangement. In some embodiments of the invention, the carrier has a band-like, tubular or cuff-like shape that facilitates the carrier at least partially encircling the organ.
The control system includes a (Analog-to-digital) ADC conversion system which provides processor system with digital signals corresponding to the analog bioelectronic signals picked up from the organ by electrode. The control system includes also a (Digital-to-analog) DAC system which provides carrier with analog signals that causes it to compress and relax in response to the digital output signals computed processor system.
This means that the apparatus needs to be regularly powered.
Moreover, in operation, in essentially the manner of a conventional solenoid, currents in wire coils create magnetic fields and corresponding forces upon magnetized members. The resulting movement of the members contract the mesh of actuators causing carrier to compress the organ to which it is applied. When the current is removed, the mesh expands again.
That means that a continuous current is needed for compressing the organ.
Therefore there are, at the present time, no adequate solutions, whether commercial or in the literature, for implanting robust devices comprising an artificial contractile structure.